In-body path loss models for implants in heterogeneous human tissues using implantable slot dipole conformal flexible antennas

A wireless body area network (WBAN) consists of a wireless network with devices placed close to, attached on, or implanted into the human body. Wireless communication within a human body experiences loss in the form of attenuation and absorption. A path loss model is necessary to account for these losses. In this article, path loss is studied in the heterogeneous anatomical model of a 6-year male child from the Virtual Family using an implantable slot dipole conformal flexible antenna and an in-body path loss model is proposed at 2.45 GHz with application to implants in a human body. The model is based on 3D electromagnetic simulations and is compared to models in a homogeneous muscle tissue medium

Ultrawideband Technology for Medical In-Body Sensor Networks: An Overview of the Human Body as a Propagation Medium, Phantoms, and Approaches for Propagation Analysis

[EN] An in-body sensor network is that in which at least one of the sensors is located inside the human body. Such wireless in-body sensors are used mainly in medical applications, collecting and monitoring important parameters for health and disease treatment. IEEE Standard 802.15.6-2012 for wireless body area networks (WBANs) considers in-body communications in the Medical Implant Communications Service (MICS) band. Nevertheless, high-data-rate communications are not feasible at the MICS band because of its narrow occupied bandwidth. In this framework, ultrawideband (UWB) systems have emerged as a potential solution for in-body highdata-rate communications because of their miniaturization capabilities and low power consumption.This work was supported by the Programa de Ayudas de Investigación y Desarrollo (PAID-01-16) at the Universitat Politècnica de València, Spain; by the Ministerio de Economía y Competitividad, Spain (TEC2014-60258-C2-1-R); and by the European FEDER funds. It was also funded by the European Union’s H2020:MSCA:ITN program for the Wireless In-Body Environ-ment Communication–WiBEC project under grant 675353.Garcia-Pardo, C.; Andreu-Estellés, C.; Fornés Leal, A.; Castelló-Palacios, S.; Pérez-Simbor, S.; Barbi, M.; Vallés Lluch, A.... (2018). Ultrawideband Technology for Medical In-Body Sensor Networks: An Overview of the Human Body as a Propagation Medium, Phantoms, and Approaches for Propagation Analysis. IEEE Antennas and Propagation Magazine. 60(3):19-33. https://doi.org/10.1109/MAP.2018.2818458S193360

Experimental Assessment of Time Reversal for In-Body to In-Body UWB Communications

[EN] The standard of in-body communications is limited to the use of narrowband systems. These systems are far from the high data rate connections achieved by other wireless telecommunication services today in force. The UWB frequency band has been proposed as a possible candidate for future in-body networks. However, the attenuation of body tissues at gigahertz frequencies could be a serious drawback. Experimental measurements for channel modeling are not easy to carry out, while the use of humans is practically forbidden. Sophisticated simulation tools could provide inaccurate results since they are not able to reproduce all the in-body channel conditions. Chemical solutions known as phantoms could provide a fair approximation of body tissues¿ behavior. In this work, the Time Reversal technique is assessed to increase the channel performance of in-body communications. For this task, a large volume of experimental measurements is performed at the low part of UWB spectrum (3.1-5.1 GHz) by using a highly accurate phantom-based measurement setup. This experimental setup emulates an in-body to in-body scenario, where all the nodes are implanted inside the body. Moreover, the in-body channel characteristics such as the path loss, the correlation in transmission and reception, and the reciprocity of the channel are assessed and discussed.This work was supported by the Programa de Ayudas de Investigacion y Desarrollo (PAID-01-16) from Universitat Politecnica de Valencia and by the Ministerio de Economia y Competitividad, Spain (TEC2014-60258-C2-1-R), by the European FEDER funds.Andreu-Estellés, C.; Garcia-Pardo, C.; Castelló-Palacios, S.; Cardona Marcet, N. (2018). Experimental Assessment of Time Reversal for In-Body to In-Body UWB Communications. Wireless Communications and Mobile Computing (Online). (8927107):1-12. https://doi.org/10.1155/2018/8927107S1128927107Fireman, Z. (2003). Diagnosing small bowel Crohn’s disease with wireless capsule endoscopy. Gut, 52(3), 390-392. doi:10.1136/gut.52.3.390Burri, H., & Senouf, D. (2009). Remote monitoring and follow-up of pacemakers and implantable cardioverter defibrillators. Europace, 11(6), 701-709. doi:10.1093/europace/eup110Scanlon, W. G., Burns, B., & Evans, N. E. (2000). Radiowave propagation from a tissue-implanted source at 418 MHz and 916.5 MHz. IEEE Transactions on Biomedical Engineering, 47(4), 527-534. doi:10.1109/10.828152Chavez-Santiago, R., Garcia-Pardo, C., Fornes-Leal, A., Valles-Lluch, A., Vermeeren, G., Joseph, W., … Cardona, N. (2015). Experimental Path Loss Models for In-Body Communications within 2.36-2.5 GHz. IEEE Journal of Biomedical and Health Informatics, 1-1. doi:10.1109/jbhi.2015.2418757Khaleghi, A., Chávez-Santiago, R., & Balasingham, I. (2010). Ultra-wideband pulse-based data communications for medical implants. IET Communications, 4(15), 1889. doi:10.1049/iet-com.2009.0692Khaleghi, A., Chávez-Santiago, R., & Balasingham, I. (2011). Ultra-wideband statistical propagation channel model for implant sensors in the human chest. IET Microwaves, Antennas & Propagation, 5(15), 1805. doi:10.1049/iet-map.2010.0537Kurup, D., Scarpello, M., Vermeeren, G., Joseph, W., Dhaenens, K., Axisa, F., … Vanfleteren, J. (2011). In-body path loss models for implants in heterogeneous human tissues using implantable slot dipole conformal flexible antennas. EURASIP Journal on Wireless Communications and Networking, 2011(1). doi:10.1186/1687-1499-2011-51Floor, P. A., Chavez-Santiago, R., Brovoll, S., Aardal, O., Bergsland, J., Grymyr, O.-J. H. N., … Balasingham, I. (2015). In-Body to On-Body Ultrawideband Propagation Model Derived From Measurements in Living Animals. IEEE Journal of Biomedical and Health Informatics, 19(3), 938-948. doi:10.1109/jbhi.2015.2417805Shimizu, Y., Anzai, D., Chavez-Santiago, R., Floor, P. A., Balasingham, I., & Wang, J. (2017). Performance Evaluation of an Ultra-Wideband Transmit Diversity in a Living Animal Experiment. IEEE Transactions on Microwave Theory and Techniques, 65(7), 2596-2606. doi:10.1109/tmtt.2017.2669039Anzai, D., Katsu, K., Chavez-Santiago, R., Wang, Q., Plettemeier, D., Wang, J., & Balasingham, I. (2014). Experimental Evaluation of Implant UWB-IR Transmission With Living Animal for Body Area Networks. IEEE Transactions on Microwave Theory and Techniques, 62(1), 183-192. doi:10.1109/tmtt.2013.2291542Chou, C.-K., Chen, G.-W., Guy, A. W., & Luk, K. H. (1984). Formulas for preparing phantom muscle tissue at various radiofrequencies. Bioelectromagnetics, 5(4), 435-441. doi:10.1002/bem.2250050408Cheung, A. Y., & Koopman, D. W. (1976). Experimental Development of Simulated Biomaterials for Dosimetry Studies of Hazardous Microwave Radiation (Short Papers). IEEE Transactions on Microwave Theory and Techniques, 24(10), 669-673. doi:10.1109/tmtt.1976.1128936YAMAMOTO, H., ZHOU, J., & KOBAYASHI, T. (2008). Ultra Wideband Electromagnetic Phantoms for Antennas and Propagation Studies. IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, E91-A(11), 3173-3182. doi:10.1093/ietfec/e91-a.11.3173Lazebnik, M., Madsen, E. L., Frank, G. R., & Hagness, S. C. (2005). Tissue-mimicking phantom materials for narrowband and ultrawideband microwave applications. Physics in Medicine and Biology, 50(18), 4245-4258. doi:10.1088/0031-9155/50/18/001Yilmaz, T., Foster, R., & Hao, Y. (2014). Broadband Tissue Mimicking Phantoms and a Patch Resonator for Evaluating Noninvasive Monitoring of Blood Glucose Levels. IEEE Transactions on Antennas and Propagation, 62(6), 3064-3075. doi:10.1109/tap.2014.2313139Gezici, S., Zhi Tian, Giannakis, G. B., Kobayashi, H., Molisch, A. F., Poor, H. V., & Sahinoglu, Z. (2005). Localization via ultra-wideband radios: a look at positioning aspects for future sensor networks. IEEE Signal Processing Magazine, 22(4), 70-84. doi:10.1109/msp.2005.1458289Marinova, M., Thielens, A., Tanghe, E., Vallozzi, L., Vermeeren, G., Joseph, W., … Martens, L. (2015). Diversity Performance of Off-Body MB-OFDM UWB-MIMO. IEEE Transactions on Antennas and Propagation, 63(7), 3187-3197. doi:10.1109/tap.2015.2422353SHI, J., ANZAI, D., & WANG, J. (2012). Channel Modeling and Performance Analysis of Diversity Reception for Implant UWB Wireless Link. IEICE Transactions on Communications, E95.B(10), 3197-3205. doi:10.1587/transcom.e95.b.3197Pajusco, P., & Pagani, P. (2009). On the Use of Uniform Circular Arrays for Characterizing UWB Time Reversal. IEEE Transactions on Antennas and Propagation, 57(1), 102-109. doi:10.1109/tap.2008.2009715Chavez-Santiago, R., Sayrafian-Pour, K., Khaleghi, A., Takizawa, K., Wang, J., Balasingham, I., & Li, H.-B. (2013). Propagation models for IEEE 802.15.6 standardization of implant communication in body area networks. IEEE Communications Magazine, 51(8), 80-87. doi:10.1109/mcom.2013.6576343Andreu, C., Castello-Palacios, S., Garcia-Pardo, C., Fornes-Leal, A., Valles-Lluch, A., & Cardona, N. (2016). Spatial In-Body Channel Characterization Using an Accurate UWB Phantom. IEEE Transactions on Microwave Theory and Techniques, 64(11), 3995-4002. doi:10.1109/tmtt.2016.2609409Pahlavan, K., & Levesque, A. H. (2005). Wireless Information Networks. doi:10.1002/0471738646Qiu, R. C., Zhou, C., Guo, N., & Zhang, J. Q. (2006). Time Reversal With MISO for Ultrawideband Communications: Experimental Results. IEEE Antennas and Wireless Propagation Letters, 5, 269-273. doi:10.1109/lawp.2006.875888Ando, H., Takizawa, K., Yoshida, T., Matsushita, K., Hirata, M., & Suzuki, T. (2016). Wireless Multichannel Neural Recording With a 128-Mbps UWB Transmitter for an Implantable Brain-Machine Interfaces. IEEE Transactions on Biomedical Circuits and Systems, 10(6), 1068-1078. doi:10.1109/tbcas.2016.251452

System design and performance analysis of wireless body area networks

One key solution to provide affordable and proactive healthcare facilities to overcome the fast world population growth and a shortage of medical professionals is through health monitoring systems capable of early disease detection and real-time data transmission leading to considerable improvements in the quality of human life. Wireless body area networks (WBANs) are proposed as promising approaches to providing better mobility and flexibility experience than traditional wired medical systems by using low-power, miniaturised sensors inside, around, or off the human body and are employed to monitor physiological signals. However, the design of reliable and energy efficient in-body communication systems is still a major research challenge since implant devices are characterised by strict requirements on size, energy consumption and safety. Moreover, there is still no agreement regarding QoS support in WBANs. The first part of this work concentrates on the design and performance evaluation of WBAN communication systems involving the ‘in-body to in-body’ and ‘in-body to on-body’ scenarios. The essential step is to derive the statistical WBAN path loss (PL) models, which characterise the signal propagation energy loss transmitting via intra-body region. Moreover, from the point of view of human body safety evaluation, the obtained specific absorption rate (SAR) values are compared with the latest Institute of Electrical and Electronics Engineers (IEEE) 802.15.6 Task Group technical standard and the International Commission on Non-Ionizing Radiation Protection (ICNIRP) safety guidelines. Link budget analysis is then presented using a range of energy-efficient modulation schemes, and the results are given including the transmission distance, data rate and transmitting power in individual sections. On the other hand, major quality of service (QoS) support challenges in WBANs are discussed and investigated. To achieve higher lifetime and lower network energy consumption, different data routing protocol methods, including incremental relaying and the two-relay based routing technique are taken into account. A set of key QoS metrics for linear mathematical models is given along with the related subjective functions. The incremental relaying routing protocol promises significant enhancements in in-body WBAN network lifetime by minimising the overall communication distance while the two-relay based routing method achieves better performance in terms of emergency data transmission and high traffic condition, QoS-aware WBANs design. Moreover, to handle real-time high data transmission applications such as capsule endoscope image transmission, a flexible QoS-aware wireless body area sensor networks (WBASNs) model is proposed and evaluated that can bring novel solutions for a realistic multi-user hospital environment regarding information packet collision probability, manageable numbers of sensor nodes and a wide range of data rates